Google’s Matt Cutts shared some new statistics in a recent video about the types of notifications Google sends out via Google Webmaster Tools. Google sends “hundreds of thousands” of messages each month to webmasters. The categories of those messages break down as follows: 90 percent of those messages are black-hat related, 4 percent are notifications of content that have little or no value add, 3 percent are hacking notifications, 2 percent are about link buying and 1 percent are about link selling. … The last time we had an update about the number or categories of types of notifications was